GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The keyless entry system is a vehicle entry device. The keyless entry will unlock/unlatch the vehicle doors or open the rear gate when a corresponding button on the key fob is pressed. This is accomplished by the key fob sending a radio frequency to the body control module (BCM). The signal is received by the BCM via an internal antenna. A low transmitter battery or radio frequency (RF) interference from aftermarket devices such as 2-way radios, power inverters, cellular phone chargers, computers, etc. may cause a system malfunction. High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction.

Diagnostic Aids

For the J 43241 Keyless Entry Tester, inspect the keyless entry transmitter part number to determine that it is the correct model for the vehicle. A wrong model transmitter may pass the test, but it will not activate the vehicle remote system.

Reference Information

Schematic Reference

Remote Function Schematics

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Scan Tool Data List

Circuit/System Testing

  1. Ignition On, verify the scan tool Remote Panic Command parameter responds to the panic function on the transmitter.
  2. If it does not respond to the panic function, refer to Keyless Entry System Inoperative .
  3. Verify that the headlamps pulse ON and OFF when the panic button is pressed.
  4. If they do not pulse ON and OFF, refer to Diagnostic Starting Point - Lighting Systems .
  5. Refer to Diagnostic Starting Point - Horns .

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Transmitter Programming for transmitter programming
    •  Control Module References for BCM replacement, setup, and programming